set up mypy for incremental adoption of 'strict optional'

setup.cfg

@@ -31,10 +31,76 @@ ignore_missing_imports = True
 follow_imports = skip
 check_untyped_defs = True
 warn_unused_ignores = True
-strict_optional = False
+strict_optional = True
 no_implicit_optional = True
 warn_redundant_casts = True
 
+[mypy-sphinx.application]
+strict_optional = False
+
+[mypy-sphinx.builders]
+strict_optional = False
+
+[mypy-sphinx.builders.gettext]
+strict_optional = False
+
+[mypy-sphinx.builders.html]
+strict_optional = False
+
+[mypy-sphinx.builders.latex.*]
+strict_optional = False
+
+[mypy-sphinx.builders.linkcheck]
+strict_optional = False
+
+[mypy-sphinx.builders.singlehtml]
+strict_optional = False
+
+[mypy-sphinx.cmd.*]
+strict_optional = False
+
+[mypy-sphinx.directives]
+strict_optional = False
+
+[mypy-sphinx.directives.code]
+strict_optional = False
+
+[mypy-sphinx.domains.*]
+strict_optional = False
+
+[mypy-sphinx.environment.*]
+strict_optional = False
+
+[mypy-sphinx.ext.*]
+strict_optional = False
+
+[mypy-sphinx.locale]
+strict_optional = False
+
+[mypy-sphinx.pycode.parser]
+strict_optional = False
+
+[mypy-sphinx.registry.*]
+strict_optional = False
+
+[mypy-sphinx.search]
+strict_optional = False
+
+[mypy-sphinx.setup_command]
+strict_optional = False
+
+[mypy-sphinx.testing.util]
+strict_optional = False
+
+[mypy-sphinx.transforms.*]
+strict_optional = False
+
+[mypy-sphinx.util.*]
+strict_optional = False
+
+[mypy-sphinx.writers.*]
+strict_optional = False
+
 [tool:pytest]
 filterwarnings =
     all

sphinx/addnodes.py

@@ -1,6 +1,6 @@
 """Additional docutils nodes."""
 
-from typing import TYPE_CHECKING, Any, Dict, List, Sequence
+from typing import TYPE_CHECKING, Any, Dict, List, Optional, Sequence
 
 import docutils
 from docutils import nodes
@@ -27,7 +27,7 @@ class document(nodes.document):
                    in your extensions.  It will be removed without deprecation period.
     """
 
-    def set_id(self, node: Element, msgnode: Element = None,
+    def set_id(self, node: Element, msgnode: Optional[Element] = None,
                suggested_prefix: str = '') -> str:
         if docutils.__version_info__ >= (0, 16):
             ret = super().set_id(node, msgnode, suggested_prefix)  # type: ignore

sphinx/builders/html/__init__.py

@@ -1023,7 +1023,7 @@ class StandaloneHTMLBuilder(Builder):
         return quote(docname) + self.link_suffix
 
     def handle_page(self, pagename: str, addctx: Dict, templatename: str = 'page.html',
-                    outfilename: str = None, event_arg: Any = None) -> None:
+                    outfilename: Optional[str] = None, event_arg: Any = None) -> None:
         ctx = self.globalcontext.copy()
         # current_page_name is backwards compatibility
         ctx['pagename'] = ctx['current_page_name'] = pagename

sphinx/config.py

@@ -424,7 +424,7 @@ def correct_copyright_year(app: "Sphinx", config: Config) -> None:
                 config[k] = copyright_year_re.sub(replace, config[k])
 
 
-def check_confval_types(app: "Sphinx", config: Config) -> None:
+def check_confval_types(app: Optional["Sphinx"], config: Config) -> None:
     """Check all values for deviation from the default value's type, since
     that can result in TypeErrors all over the place NB.
     """

sphinx/io.py

@@ -182,7 +182,7 @@ def read_doc(app: "Sphinx", env: BuildEnvironment, filename: str) -> nodes.docum
                     writer=SphinxDummyWriter(),
                     source_class=SphinxFileInput,
                     destination=NullOutput())
-    pub.process_programmatic_settings(None, env.settings, None)
+    pub.process_programmatic_settings(None, env.settings, None)  # type: ignore[arg-type]
     pub.set_source(source_path=filename)
     pub.publish()
     return pub.document

sphinx/jinja2glue.py

@@ -3,7 +3,7 @@
 import pathlib
 from os import path
 from pprint import pformat
-from typing import TYPE_CHECKING, Any, Callable, Dict, Iterator, List, Tuple, Union
+from typing import TYPE_CHECKING, Any, Callable, Dict, Iterator, List, Optional, Tuple, Union
 
 from jinja2 import BaseLoader, FileSystemLoader, TemplateNotFound
 from jinja2.environment import Environment
@@ -142,7 +142,12 @@ class BuiltinTemplateLoader(TemplateBridge, BaseLoader):
 
     # TemplateBridge interface
 
-    def init(self, builder: "Builder", theme: Theme = None, dirs: List[str] = None) -> None:
+    def init(
+        self,
+        builder: "Builder",
+        theme: Optional[Theme] = None,
+        dirs: Optional[List[str]] = None
+    ) -> None:
         # create a chain of paths to search
         if theme:
             # the theme's own dir and its bases' dirs

sphinx/testing/fixtures.py

@@ -5,7 +5,7 @@ import sys
 from collections import namedtuple
 from io import StringIO
 from subprocess import PIPE
-from typing import Any, Callable, Dict, Generator, Tuple
+from typing import Any, Callable, Dict, Generator, Optional, Tuple
 
 import pytest
 
@@ -28,7 +28,7 @@ def pytest_configure(config):
 
 
 @pytest.fixture(scope='session')
-def rootdir() -> str:
+def rootdir() -> Optional[str]:
     return None
 
 

sphinx/testing/path.py

@@ -2,7 +2,7 @@ import builtins
 import os
 import shutil
 import sys
-from typing import IO, Any, Callable, List
+from typing import IO, Any, Callable, List, Optional
 
 FILESYSTEMENCODING = sys.getfilesystemencoding() or sys.getdefaultencoding()
 
@@ -69,7 +69,7 @@ class path(str):
         """
         return os.path.ismount(self)
 
-    def rmtree(self, ignore_errors: bool = False, onerror: Callable = None) -> None:
+    def rmtree(self, ignore_errors: bool = False, onerror: Optional[Callable] = None) -> None:
         """
         Removes the file or directory and any files or directories it may
         contain.